In modern automotive fuel injection systems, a fuel pump is mounted in a reservoir in a fuel tank and supplies fuel in excess of maximum engine demand. The surplus or overage is returned to the fuel tank. Proposals have been made to confine the overage to the reservoir to prevent mixing of the overage with bulk fuel and thereby remove a source of heating of the bulk fuel. For example, United States patent application Ser. No. 07/656,668, filed Feb. 15, 1991 and assigned to the assignee of this invention, describes a fuel system in which the reservoir is sealed and kept filled by a combination of overage and discharge of a low pressure jet pump. The jet pump recirculates reservoir overflow back into the reservoir in preference to bulk fuel from the fuel tank. U.S. Pat. No. 4,878,518 describes a fuel system in which a valve on a low pressure jet pump closes when the combination of jet pump discharge and overage exceeds the capacity of a sealed reservoir. U.S. Pat. No. 4,865,522 describes a fuel system in which a standpipe in a reservoir prevents escape of overage from the reservoir except when fuel in the reservoir overflows the standpipe. A fuel system according to this invention has a reservoir with a fuel pump therein and incorporates novel structure for supplying the fuel pump with overage in preference to bulk fuel.